This question has been addressed in 1 Texas court opinion:
COA14 — January 29, 2026
Stanley Lewis II appealed his intoxication manslaughter conviction, arguing that the victim's extreme intoxication (.233 BAC) and potential presence in the lane of traffic—rather than his own impairment—were the true causes of the fatal accident. The Fourteenth Court of Appeals analyzed the causation requirements under the Texas Penal Code, determining that Lewis’s failure to maintain a single lane, his increased speed, and his failure to brake established a sufficient "but-for" causal link to the death. The court affirmed the conviction, holding that a defendant's criminal liability is not negated by the victim’s concurrent negligence or intoxication when the defendant’s own impaired actions led to the fatal maneuver.
Litigation Takeaway
“In custody disputes involving substance abuse, a parent cannot escape a finding of endangerment by simply pointing to the other parent's "unclean hands" or concurrent intoxication. This case demonstrates that if a parent’s impairment leads to a dangerous maneuver or failure to avoid an accident, the other party's conduct is legally irrelevant to the determination of fault and safety risk.”